JPS6040004B2 - lens barrel - Google Patents

Description

Detailed Description of the Invention The present invention relates to a lens barrel, and in particular, the rotational force of the distance adjustment ring of the lens barrel changes from close range to telephoto (infinite distance).
The present invention relates to a lens barrel in which the rotational force of the distance adjustment ring is not uniform until then, but changes from a certain distance, and the amount of extension of the distance adjustment ring is determined from this change.

With conventional lenses, when adjusting the distance to a subject by looking through the camera's viewfinder, if you wanted to know the distance to the subject, you had to read the distance scale engraved on the lens barrel.

This task of reading the distance scale is inconvenient when shooting continuously or shooting on floors.

In addition, in the case of telephoto and super telephoto shooting, it is necessary to quickly adjust the distance to the optimum distance when rotating and moving the Shins lens barrel, and to adjust the distance accurately after that. It is convenient to prevent the amount of rotation of the distance ring (the amount of lens extension) from becoming too large by avoiding the force required for rotation and making it necessary for .

Embodiments of the present invention will be illustrated and described in detail below.

1 to 4 show a first embodiment of the present invention, in which FIG. 1 is a sectional view of a main part of a telephoto lens 1, and FIG. 2 is a sectional view taken along the line A-A' in FIG.
FIG. 3 is a sectional view taken along the line B-B' in FIG. 2, and FIG. 4 is a cam diagram, which will be described later.

In the figure, reference numeral 2 denotes a distance adjustment ring for the photographing lens L, and the rotation shaft 4 of the distance adjustment ring 2 is pivotally supported by a gear box 8 fixed to a fixed ring 6 of the lens barrel. A cam 10 for changing the rotational force of the lens L and a pinion 12 for adjusting the travel distance of the lens L are fixed to the rotating shaft 4. The pinion 12 meshes with the rack 14, and the rack 14 is fixed to the movable lens barrel 16 that holds the lens L, and the amount of rotation of the pinion 12 changes to the amount of movement of the rack 14 and the movable lens barrel 16 in all directions of the optical axis. The cam 10 is an eccentric cam fixed to the rotating shaft 4 with a key or the like, as shown in FIG.

Reference numeral 18 denotes a pin to which a spring force is applied by a spring 20 so as to push the cam 1 from a part of the gear box 8, and the cam 10 is rotated by rotation of the distance adjustment handle 2, and the cam 10 is placed at a certain eccentric position. It comes into contact with pin 18.

Next, the operation of the first embodiment shown in FIGS. 1 to 3 will be explained. When the telephoto lens 1 is attached to a camera (not shown) and the distance is adjusted, when the distance adjustment handle is rotated while looking through the camera's finder, the rotation is performed by the rotation shaft 4, pinion 12, rack 14, and movable lens barrel 16. The transmission lens L moves in proportion to the amount of rotation of the distance adjustment ring 2.

When the distance adjustment handle 2 is rotated, the cam 10 also rotates at the same time as the pinion rotates, and as the cam 10 rotates at a certain position, it comes into contact with the pin 18. Since the spring force of the spring 20 is added, it becomes heavy.

Therefore, the photographer can know that the distance adjustment ring has rotated by more than a certain value due to a change in the rotational force of the distance adjustment handle of the lens, and that the amount of movement of the lens has exceeded a predetermined value. FIG. 4 shows an example of a cam diagram of the cam 10, where the horizontal axis shows the pitch circle of the cam, and the vertical axis shows the rotational force (load) of the distance adjusting ring 2 or the distance adjusting ring 2 via the cam of the spring.
Indicates the spring force applied to

F, is the constant amount of rotational force of the distance adjustment ring 2 when the pin 18 does not support the cam, F2 is the rotational force of F, on the distance adjustment ring 2 from point b, where the pin starts contacting the cam, to point 1. The rotational force applied to F is the amount of change in the spring force of the spring.

In this embodiment, when the distance adjusting ring 2 is rotated to adjust the distance, the cam 10 does not touch the pin 18.
The rotational force during the rotational distance b is F, and the cam 10 is
As shown in FIG. 4, the load of the rotational force increases during the rotational distance from b to a where the contact point 8 comes into contact.

The rotational force from the vicinity of point c to the vicinity of point d increases to F, 10F2, and the amount of movement of the distance adjustment ring can be known from the change in rotational force. 5 to 8 show a second embodiment of the present invention, in which FIG. 5 is a sectional view of a telephoto lens, FIGS. 6 and 7 are exploded views of a cam provided in a lens barrel, and FIG. FIG. 8 shows a configuration diagram of the main parts of this embodiment.

30 is a front lens barrel part, 32 is a rear lens barrel part, and the fixed lens barrel part 3
2 is provided with a linear guide groove 32a, and the linear guide groove has an elastic roller 38 supported by a pin 36 that slides in the guide groove 32a as the distance adjustment ring 34 rotates.

The movable lens barrel holding the 40' lenses L2 is configured to move back and forth in the optical axis direction by rotation of the distance adjustment ring 34.

FIG. 8 shows the structure of the guide groove 32a, the bottle 36, and the roller 38. Reference numeral 34a denotes a cam groove provided in the distance adjustment ring. A part of the roller 38 is iron-fitted to the cam groove 34a, and the roller 38, which is rotatably supported by the pin 36 by rotation of the distance adjustment ring 34, is rotated by the cam base 34a. The movable lens barrel 40 fixed to the rear lens barrel portion is moved by sliding through both grooves while being iron-coupled with the guide groove 32a.

FIG. 6 is a developed view of the cam groove 34a provided in the distance adjustment ring 34, and shows the case where the cam groove is straight. When the cam groove is straight, the distance scale is not equally spaced depending on the distance as shown in the figure, but at long distances. As the distance increases, the scale interval becomes narrower, and therefore the adjustment lens can be adjusted by a small amount of rotation of the distance adjustment ring 34.
The amount of adjustment becomes larger, and the farther the distance, the more difficult it becomes to adjust the distance. In order to solve this problem, a lens having a cam groove 34b as shown in Fig. 7 is designed in which the inclination angle of the cam groove is changed from a certain position so that the distance scale intervals are as equal as possible even at long distances. is proposed. 7th
For a distance adjustment ring with a cam groove as shown in the figure, the oblique angle of the cam groove is large at short distances and small at long distances, so the rotational force is heavy at short distances and light at long distances, but this is not the case in actual shooting. Especially in the case of a telephoto or super-telephoto lens, it is convenient for the distance adjustment ring to rotate lightly when adjusting the distance at close distances, and to rotate more heavily when adjusting the distance at long distances.

In this embodiment, as shown in Fig. 8, the width b of the guide groove in which the elastic rollers slide in parallel is set to a width b that deforms within the elastic deformation range of the rollers above a certain value on the distance scale. This increases the rotational force of the distance adjustment ring and informs the photographer of the distance adjustment value. FIG. 9 shows an embodiment in which a cam groove 52 of a zoom lens is used, which has a step in the groove width of the cam groove shown in the previous embodiment. The roller 54 having a
is deformed to change the rotational force of the cylinder 52 from point a, and this change in rotational force (increase in rotational load) notifies the photographer of the actual distance to point V.

10 to 12 show other embodiments.
In the figure, a hole 60 containing a spring 58 is provided in a part of a fixed lens barrel 56 that holds a movable lens frame (not shown), and the spring 58
A ball 62 having a repulsive force is held between a movable member 64 fixed to a zoom ring or a zoom link.

Reference numeral 64a denotes a stepped portion provided on the inner fluff side of the movable member 64. The distance between the fixed lens barrel 56 and the movable member 64 is different on the left and right sides of this stepped portion, and as the movable member 64 rotates in the direction of the arrow shown in the figure, the ball 62 runs onto the stepped portion 64a of the movable portion village 64.

The rotation of the zoom ring or the movable part becomes heavy due to the spring force of the spring 58, and the photographer can know the amount of extension of the photographic lens from the difference in the load required for rotation. FIG. 11 utilizes the change in rotational force due to the difference in the distance between the fixed lens barrel 66 and the zoom ring or movable member 68 in the thrust direction, and the structure and operation are the same as in FIG. 10, so a description thereof will be omitted.

FIG. 12 shows an example in which a key is used as a guide member of a movable lens barrel. Reference numeral 70 is a key fixed to a fixed ring (not shown), and a key of a movable ring 72 that holds a photographic lens (not shown). It is slidably fitted into the groove 72a.

The moving ring 72 is made of an elastic material such as a resin material, and the key 7
0 is provided with a stepped portion 70a, and when the movable ring 72 is slid and the end of the keyway 72a of the ring 72 comes into contact with the stepped portion of the key 70, the movable ring 72 deforms within the allowable range of elastic deformation. Slides into contact with the key. Therefore, as the movable ring 72 is elastically deformed, a load is applied to the sliding movement of the movable ring 72, causing a change in the sliding force of the movable ring 72 before and after the stepped portion 70a of the key 70. Therefore, the photographer can know the value of the distance scale, ie, the amount of extension of the photographic lens, by the change in the sliding force of the movable ring (or the rotational force of the distance adjustment ring that slides the movable ring). As described above, the present invention provides a lens barrel that adjusts the amount of extension of a taking lens linked to a distance adjustment ring by rotation of the distance adjustment ring, and a lens barrel that converts the amount of rotation of the distance adjustment ring into the amount of extension of the taking lens. A load means such as a cam spring and a rigid part provided in the cam groove is provided, and when the amount of rotation of the distance adjustment ring exceeds a certain value, the load of the load means is applied to the distance adjustment ring, reducing the rotational force of the distance adjustment ring. This lens barrel allows you to know the amount of extension of the distance adjustment ring (the amount of movement of the photographic lens) based on changes in the distance adjustment ring.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an embodiment in which the present invention is applied to a telephoto lens. FIG. 2 is a sectional view taken along line A-A' in FIG. Figure 3 is Figure 2 B-B
'Cross-sectional view. FIG. 4 is an example of a cam diagram of the cam 10. FIG. 5 is a sectional view of a telephoto lens showing a second embodiment of the present invention. 6th
The figure is an exploded view of a straight type cam groove. FIG. 7 is another developed view of the cam groove. FIG. 8 is a plan view of the straight guide groove. FIG. 9 is a perspective view of the cam barrel of the zoom lens. FIGS. 10 and 11 are sectional views of main parts of other embodiments of the present invention. FIG. 12 is a configuration diagram of main parts of an embodiment of the present invention using a key. 1...Telephoto lens, 2...
...Distance adjustment handle, 4...Rotation axis, 8...
...Garbox, 10...Cam, 12...
...Pinion, 16...Moving lens barrel, 18...
Pin, 20...Spring, F゜''...A certain amount of rotational force of the distance adjustment ring 2 when the pin 18 does not contact the cam, F2.
...Rotational force of the distance adjustment ring 2 when the pin 18 contacts the cam, 30...Front lens barrel, 32...Rear barrel, 38...Elasticity Colo with 40・
...Moving lens barrel. Koji' figure 2 figure 3 surprising hair figure 3 figure 8 purple figure younger brother evening! Phantom brother Nori doctor A plan // Medical doctor D plan/Diagram 2

Claims (1)

[Claims] 1. A movable lens barrel holding the lens is fitted into a fixed barrel having a guide groove for guiding a lens moving in a direction parallel to the optical axis, and a cam groove intersecting with the guide groove is provided on the outside of the fixed barrel. A rotating barrel is fitted, and a pin implanted in the movable lens barrel and an elastic roller fitted to the pin are engaged at the intersection of the guide groove of the fixed barrel and the cam groove of the rotating barrel, and the guide groove of the guide groove is fitted into the rotating barrel. The groove width is set to a width that deforms within the range of elastic deformation of the rollers over a certain range of the moving region of the lens, and the moving force of the lens is changed by the elastic deformation of the rollers. lens barrel.